I had a similar problem with my Generac that's in my 2002 Lance. It turned out that the diaphragm in the vaporizer was stuck. Opened up the lp vaporizer cleaned the diaphragm and no problems since.
I have a 1997 f350 dually and it calls for 215s. I bought it used and it had 235s. So when it needed new tires I went with the 235s and never had any problems until I tried some Goodrich commercial t/a tires. I had always used Cooper tires before but...
My '97 F350 with the 7.3 has 4:10 and they have been great with my 4k slide in. With the new trucks having so much more hp/torque I thought that I could pick up a few mpgs with different gears.